The study is a four-part" open-label, Phase I, 8 week drug interaction study. Parts A and B will examine the effects of fluconazole and rifabutin or clarithromycin, together and alone, on the pharmacokinetics of sulfamethoxazole (SMX). Parts C and D will examine the effects of fluconazole and rifabutin or clarithromycin, together and alone, on the pharmacokinetics of dapsone.